Sheet member and method of manufacturing sheet member

ABSTRACT

In an outer covering sheet of an absorbent product, first, second and third adhesive layer elements each extending in a left-right direction are formed on a second covering sheet by spiral spray application. Each of these adhesive layer elements has wide width parts and narrow width parts which are continuous with the wide width parts, respectively. Therefore, hot melt adhesive can be stably discharged across the entire length of the adhesive layer element, unlike in the case where only wide width parts are formed intermittently. As a result, it is possible to obtain the outer covering sheet which is a sheet member having the adhesive layer elements with desired shapes where unevenness is decreased. In the absorbent product which is manufactured with use of the sheet member, the comfort level of the wearer can be prevented from decreasing due to unevenness of thickness of the adhesive layer elements.

TECHNICAL FIELD

The present invention relates to a sheet member to be used formanufacturing an absorbent product and a method of manufacturing thesheet member.

BACKGROUND ART

In the manufacture of an absorbent product, an elastic member isconventionally bonded to a nonwoven fabric with hot melt adhesive or thelike. For example, in an absorbent product disclosed in Japanese PatentApplication Laid-Open No. 2006-130042 (Document 1), elastic members forlegs are bonded to a middle part of an outer covering sheet and innercovering sheet, and hot melt adhesive is applied all over the middlepart (containing areas where the elastic members for legs do not exist)in a spiral manner.

On the other hand, in Japanese Patent Publication No. 2664501 (Document2) and Japanese Patent Publication No. 2954624 (Document 3), a techniqueis disclosed in which a spiral shaped adhesive is formed by applyingadhesive spirally along a left-right direction of a disposable diaper ina short distance and elastic members are bonded to a nonwoven fabricwith a plurality of spiral shaped adhesives arranged in a longitudinaldirection of the disposable diaper.

In a disposable diaper disclosed in Japanese Utility Model ApplicationLaid-Open No. 61-137607 (Document 4), hot melt adhesive is appliedintermittently and linearly in a left-right direction at an adhesionposition of elastic member for waist gathers and intermittent straightlines of the hot melt adhesive are arranged in an up-down direction, toform intermittent adhesive parts. In the disposable diaper of Document4, clearances of the hot melt adhesive in respective intermittentstraight lines (i.e., the clearances are distances of spaces where thehot melt adhesive is not applied) become larger toward a waist opening.

Japanese Patent Publication No. 2619595 (Document 5) discloses anapparatus for manufacturing an absorbent product. In a curtain coaterthereof for discharging hot melt adhesive in curtain-like form, the hotmelt adhesive is intermittently discharged from a plurality of outletsarranged so as to lie across a sheet and therefore the hot melt adhesiveis applied only onto positions on the sheet where elastic members are tobe bonded.

In the absorbent product of Document 1, since the hot melt adhesive isuniformly applied over a wide area, the amount of hot melt adhesive islarge and the manufacturing cost of the absorbent product increases.Also there is a limit to improve the softness of the absorbent product.

On the other hand, in the disposable diapers of Documents 2 to 5, whenadhesive is applied, the steps of discharging the adhesive from a nozzlefor a short time, stoppage of discharging, and discharging the adhesivefor a short time are repeated. Thus, application control of the adhesiveis complicated. In addition, since it is difficult to discharge theadhesive stably just after start of discharging, a lump of adhesivefalls at a starting end of spiral shaped adhesive and so on, whichcauses unevenness (i.e., mura) of adhesive.

SUMMARY OF INVENTION

The present invention is intended for a sheet member to be used formanufacturing an absorbent product. It is an object of the presentinvention to obtain such a sheet member having an adhesive layer elementwhere unevenness is suppressed.

The sheet member according to the present invention comprises: a sheet;and an adhesive layer element lying on the sheet and extending in afirst direction; wherein the adhesive layer element comprises: a widewidth part which is formed by applying string-like adhesive onto thesheet along the first direction with vibration of the adhesive in asecond direction orthogonal to the first direction; and a narrow widthpart which is narrower than the wide width part and which is formed byapplying the string-like adhesive onto the sheet along the firstdirection with or without vibration of the adhesive in the seconddirection, the narrow width part being continuous with the wide widthpart.

In the present invention, it is possible to obtain the sheet memberhaving the adhesive layer element where unevenness is suppressed.

According to a preferred embodiment of the present invention, the narrowwidth part has a linear shape extending in the first direction.Therefore, a difference in width between the wide width part and thenarrow width part can be large, and breathability and softness of thesheet member can be increased.

According to another preferred embodiment of the present invention, theadhesive layer element comprises a plurality of wide width parts and aplurality of narrow width parts which are arranged in the firstdirection alternately and continuously. Therefore, areas on which theadhesive layer element is not formed are located almost evenly on thesheet member. As the result, breathability and softness of the sheetmember are increased almost uniformly.

In this case, according to an aspect of the present invention, a widthof each wide width part and each narrow width part gradually changesalong the first direction, and a plurality of rhombus patterns arearranged along the first direction in the adhesive layer element.According to another aspect of the present invention, the sheet memberfurther comprises another adhesive layer element which has the samestructure as the adhesive layer element, extending in the firstdirection and being adjacent to the adhesive layer element in the seconddirection. Preferably, the plurality of wide width parts in the adhesivelayer element are adjacent to a plurality of narrow width parts in theanother adhesive layer element in the second direction, respectively,and the plurality of narrow width parts in the adhesive layer elementare adjacent to a plurality of wide width parts in the another adhesivelayer element in the second direction, respectively. As the result,breathability and softness of the sheet member are increased moreuniformly.

According to still another preferred embodiment of the presentinvention, the sheet member further comprises another sheet which isbonded to the sheet with the adhesive layer element. In this case,preferably, the sheet member further comprises an elastic member whichis located between the sheet and the another sheet and which is bondedto the sheet and the another sheet with the adhesive layer element. Morepreferably, the wide width part of the adhesive layer element is locatedon an area where the elastic member exists and the narrow width part islocated on an area where the elastic member does not exist. In thissheet, the elastic member can be firmly bonded to the sheet and theanother sheet.

In the case where the sheet member comprises the another adhesive layerelement, the sheet member may further comprise: another sheet which isbonded to the sheet with the adhesive layer element and the anotheradhesive layer element; and super absorbent polymers or super absorbentfibers which lie between the sheet and the another sheet, and which arelocated at least at an area between the adhesive layer element and theanother adhesive layer element. It is therefore possible to easilydeform the sheet member having the super absorbent polymers or the superabsorbent fibers.

Preferable adhesive layer element is formed by spiral spray application.

The present invention is also intended for a method of manufacturing asheet member to be used for manufacturing an absorbent product. Themethod of manufacturing a sheet member according to the presentinvention comprises the steps of: a) preparing a sheet; and b) formingan adhesive layer element lying on the sheet and extending in a firstdirection; wherein the step b) comprises the steps of: b1) forming awide width part by applying string-like adhesive onto the sheet alongthe first direction with vibration of the adhesive in a second directionorthogonal to the first direction; and b2) forming a narrow width partwhich is narrower than the wide width part, by applying the string-likeadhesive onto the sheet along the first direction with or withoutvibration of the adhesive in the second direction, the narrow width partbeing continuous with the wide width part.

These and other objects, features, aspects and advantages of the presentinvention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing an appearance of an absorbentproduct in accordance with a first preferred embodiment;

FIG. 2 is a plan view of the absorbent product in a state where theabsorbent product is developed;

FIGS. 3 and 4 are cross-sectional views of the absorbent product;

FIGS. 5 and 6 are flowcharts showing an operation flow for manufacturingan outer covering sheet;

FIGS. 7 and 8 are plan views of the outer covering sheet in the courseof manufacturing;

FIG. 9 is a view showing another example of adhesive layer elements;

FIG. 10 is a plan view showing a polymer sheet in accordance with asecond preferred embodiment;

FIG. 11 is a cross-sectional view of the polymer sheet;

FIG. 12 is a flowchart showing an operation flow for manufacturing thepolymer sheet;

FIG. 13 is a plan view showing another example of polymer sheet;

FIGS. 14 to 17 are plan views showing other examples of adhesive layerelements;

FIG. 18 is a plan view showing another example of sheet member.

DESCRIPTION OF EMBODIMENTS

FIG. 1 is a perspective view showing an appearance of an absorbentproduct 1 comprising an outer covering sheet which is a sheet member inaccordance with a first preferred embodiment of the present invention.As shown in FIG. 1, the absorbent product 1 is a pants-type (i.e.,pull-up type) disposable diaper which has a waist opening 11 at an upperend being an end on the upper side of FIG. 1 and a pair of leg openings12 on a lower part, and it receives excrement from a wearer.

FIG. 2 is a plan view of the absorbent product 1 in a state where theabsorbent product 1 is developed and in FIG. 2, the absorbent product 1is viewed from the wearer's side. As shown in FIG. 2, the absorbentproduct 1 has an outer covering sheet 4, a sheet-like absorber 20 whichis attached on the outer covering sheet 4 to absorb excrement from thewearer (i.e., the absorber 20 is located on the wearer's side of theouter covering sheet 4), and two end holding sheets 5 which are bondedto the outer covering sheet 4 at both ends of absorber 20 in itslongitudinal direction (i.e., an up-down direction in FIG. 2). Each endportion of absorber 20 in the longitudinal direction is caught betweenthe end holding sheet 5 and the outer covering sheet 4 to be fixed.

In the absorbent product 1, an upper portion in FIG. 2 is to bepositioned on the front side (stomach side) of the wearer, and a lowerportion in FIG. 2 is to be positioned on the back side of the wearer. Inthe following description, the portions of the absorbent product 1 whichare to be positioned on the front side and the back side of the wearerare referred to as a “front part” and a “back part”, respectively, and aportion to face a crotch region of the wearer at a position between thefront part and the back part is referred to as a “middle part”.

As shown in FIG. 1, in the absorbent product 1, the outer covering sheet4 is folded at the middle part together with the absorber 20. In thestate where the middle part is located on the downside, left and rightends of the front part (i.e., both ends in a left-right directionorthogonal to the longitudinal direction) are bonded to left and rightends of the back part, respectively. Therefore, the waist opening 11 isformed at upper ends of the front part and the back part, and on thedownside of the front part and the back part, the pair of leg openings12 is formed on left and right sides of the middle part, to thereby formthe absorbent product 1 in a shape of underpants.

FIG. 3 is a cross-sectional view of the absorbent product 1 taken alonga line III-III in FIG. 2 (i.e., a cross-sectional view at the middlepart). In FIG. 3, respective constituents of the absorbent product 1 aredrawn to be slightly apart from one another for easy understanding ofthe drawing (the same applies to FIG. 4). The absorber 20 has asheet-like main body part 2 and a pair of side sheets 3 located on bothside portions of the main body part 2 (i.e., both sides of the main bodypart 2 in the left-right direction), and the pair of side sheets 3extends across almost the entire length of the main body part 2 in thelongitudinal direction. The main body part 2 has a top sheet 21, a backsheet 23 and an absorbent core 22 which is located between the top sheet21 and the back sheet 23. The contour of the absorbent core 22 is drawnby thick broken lines in FIG. 2 for easy understanding of the drawing.As shown in FIG. 2, a width of the absorbent core 22 at each of the twoends in the longitudinal direction is larger than that at middle in thelongitudinal direction. In other words, the absorbent core 22 is formedin a form of hourglass.

As shown in FIG. 3, each side sheet 3 has a side sheet main body 31 andan elastic member 35 which is bonded to the side sheet main body 31 withhot melt adhesive or the like. The elastic member 35 is bonded to a freeedge (a free end) of the side sheet main body 31 along the free edge.

As shown in FIG. 3, each of the pair of side sheets 3 has a strip-likebonded part 33 and a side wall part 34. The bonded part 33 is one of twoportions divided by a folding line 39 extending across almost the entirelength thereof in the longitudinal direction, and the side wall part 34is the other of the two portions. The pair of bonded parts 33 is locatedin the vicinity of both side edges of the main body part 2, it liesacross almost the entire length thereof in the longitudinal direction,and it is bonded on the upper side (i.e., the wearer's side) of the mainbody part 2 with hot melt adhesive. Each side wall part 34 is continuousfrom the bonded part 33 at an outside edge (i.e., an edge located on theoutside in the left-right direction) of the bonded part 33 which is thefolding line 39, and on the side portion of the main body part 2, itextends across almost the entire length of the main body part 2 in thelongitudinal direction.

Each side wall part 34 is in touch with the bonded part 33 at both endportions thereof in the longitudinal direction, and it is fixed on thebonded part 33 by heat bonding or ultrasonic bonding. In the followingdescription, a portion fixed on the bonded part 33 in the side wall part34 is referred to as a “side wall end part 341”. In FIG. 2, hatchinglines are drawn at each side wall end part 341 of the side sheet 3 foreasy understanding of the drawing. As shown in FIGS. 2 and 3, the sidewall part 34 has a standing part 342 standing up from the main body part2 at a middle portion thereof in the longitudinal direction and it iscontinuous from the two side wall end parts 341. In the side wall part34, the elastic member 35 shown in FIG. 3 contracts to form gathers inthe standing part 342.

FIG. 4 is a cross-sectional view of the absorbent product 1 taken alonga line IV-IV in FIG. 2. As shown in FIGS. 3 and 4, the outer coveringsheet 4 has a first covering sheet 41 and a second covering sheet 42,and the second covering sheet 42 is layered on the lower side (i.e., theside not facing the wearer) of the first covering sheet 41. As shown inFIG. 4, each end of the second covering sheet 42 in the longitudinaldirection is folded upward (i.e., toward the wearer) so as to be bondedon the end holding sheet 5 which is bonded on the first covering sheet41.

The outer covering sheet 4 has a plurality of leg elastic members 43(six leg elastic members in the present embodiment) and a plurality ofwaist elastic members 44 (twenty-six waist elastic members in thepresent embodiment), and these elastic members are located between thefirst covering sheet 41 and the second covering sheet 42 or two layersof the second covering sheet 42 which are formed as a double-layeredstructure by folding the each end in the longitudinal direction. The legelastic members 43 and the waist elastic members 44 shown in FIGS. 2 and4 are bonded to the first covering sheet 41 and the second coveringsheet 42 with after-mentioned adhesive layer elements extending on thesecond covering sheet 42 in the left-right direction, in the state whereeach of the elastic members is stretched (i.e., the stretched legelastic members 43 and the stretched waist elastic members 44 arebonded). The adhesive layer elements are formed of hot melt adhesive.

In the absorbent product 1, by contraction of the leg elastic members43, the first covering sheet 41 and the second covering sheet 42 arecontracted to form leg gathers. Also the waist elastic members 44contract to form waist gathers. On the second covering sheet 42, the endholding sheets 5 and the back sheet 23 of the absorber 20 are bondedwith hot melt adhesive or the like. In FIG. 4, the hot melt adhesiveused for bonding of the leg elastic members 43 and bonding of the waistelastic members 44 is not shown.

The top sheet 21 shown in FIGS. 3 and 4 is a nonwoven fabric made ofliquid-pervious sheet material, for example, hydrophilic fibers, and thetop sheet 21 immediately catches moisture of excrement from the wearerand moves the moisture into the absorbent core 22. Examples of nonwovenfabrics used for the top sheet 21 are a point-bond nonwoven fabric,air-through nonwoven fabric, spunlace nonwoven fabric and spunbondnonwoven fabric, and as hydrophilic fibers for making these nonwovenfabrics, normally, cellulose, rayon, cotton and the like are used. Asthe top sheet 21, a liquid-pervious nonwoven fabric made of hydrophobicfibers (for example, polypropylene, polyethylene, polyester, polyamideor nylon) where hydrophilic treatment is performed on its surface with asurfactant may be utilized.

The absorbent core 22 is formed by wrapping a mixture of hydrophilicfibers such as crushed pulp fibers or cellulose fibers and superabsorbent material such as granulated super absorbent polymers (e.g.,SAP (Super Absorbent Polymer)) or super absorbent fibers in a tissuepaper, a liquid-pervious nonwoven fabric or the like, and the absorbentcore 22 rapidly absorbs and retains the moisture which has passedthrough the top sheet 21. The tissue paper, the liquid-pervious nonwovenfabric or the like to wrap the hydrophilic fibers, is bonded to thehydrophilic fibers and the absorbent material with hot melt adhesive, toprevent deformation of the hydrophilic fibers and falling of theabsorbent material (especially, falling after absorption of moisture).In the present embodiment, the absorbent core 22 includes pulp fibersand SAP.

As the back sheet 23, used is a water-repellent or liquid-imperviousnonwoven fabric (for example, a spunbond nonwoven fabric, meltblownnonwoven fabric or SMS (spunbond-meltblown-spunbond) nonwoven fabric)made of hydrophobic fibers, or a water-repellent or liquid-imperviousplastic film. The back sheet 23 prevents moisture of excrement or thelike which has come to the back sheet 23, from leaking out to the outerside of the main body part 2. In a case where a plastic film is used forthe back sheet 23, it is preferable that a plastic film withpermeability (breathability) is used, from the view point of preventingsweatiness in the absorbent product 1 and providing comfortable feelingto the wearer.

As the side sheet main body 31, used is a water-repellent orliquid-impervious nonwoven fabric (for example, a spunbond nonwovenfabric, meltblown nonwoven fabric or SMS nonwoven fabric) made ofhydrophobic fibers. For example, a polyurethane yarn, strip-likepolyurethane film, yarn-like or strip-like natural rubber, or the likeis used as the elastic member 35. In the present embodiment, apolyurethane yarn is used as the elastic member 35. Similar material tothe top sheet 21 or similar material to the side sheet main body 31 isused for the end holding sheets 5.

As the first covering sheet 41 and the second covering sheet 42 of theouter covering sheet 4, used is a water-repellent or liquid-imperviousnonwoven fabric made of hydrophobic fibers, or a water-repellent orliquid-impervious plastic film in a similar fashion to the back sheet23. A laminated sheet of the nonwoven fabric and the plastic film may beused. It is preferable that the plastic film has permeability(breathability). In a similar fashion to the top sheet 21, a nonwovenfabric made of hydrophilic fibers or a liquid-pervious nonwoven fabricmade of hydrophobic fibers where hydrophilic treatment is performed maybe utilized as the first covering sheet 41 and the second covering sheet42. As the leg elastic member 43 and the waist elastic member 44, forexample, a polyurethane yarn, strip-like polyurethane film, yarn-like orstrip-like natural rubber, or the like is used in a similar fashion tothe elastic member 35 of the side sheet 3. In the present embodiment, apolyurethane yarn is utilized as the leg elastic member 43 and the waistelastic member 44.

Next, discussion will be made on manufacture of the outer covering sheet4 which is one of sheet members to be used for manufacturing theabsorbent product 1. FIGS. 5 and 6 are flowcharts showing an operationflow for manufacturing the outer covering sheet 4, and FIGS. 7 and 8 areplan views showing the outer covering sheet 4 in the course ofmanufacturing. In the manufacture of the outer covering sheet 4, first,the second covering sheet 42 shown in FIG. 7 is prepared (Step S11). Inactual manufacturing process of the outer covering sheet 4, a continuoussheet body where a plurality of second covering sheets 42 are continuousin a left-right direction (i.e., the left-right direction in FIG. 7) isprepared.

Subsequently, in an apparatus for manufacturing the absorbent product 1,string-like hot melt adhesive is discharged from each of a plurality ofnozzles located above the second covering sheet 42 and arranged in thelongitudinal direction orthogonal to the left-right direction (i.e., thelongitudinal direction is a vertical direction in FIG. 7 and hereinafterreferred to as the “vertical direction”), while the second coveringsheet 42 is moved in the left-right direction. Therefore, as shown inFIG. 7, a plurality of adhesive layer elements 45, 46, 47 each extendingin the left-right direction are formed on an upper surface (i.e.,surface facing the wearer) of the second covering sheet 42 (Step S12).The hot melt adhesive used for formation of the adhesive layer elements45, 46, 47 is olefin hot melt adhesive, rubber hot melt adhesive, EVA(Ethylene-Vinyl Acetate) hot melt adhesive or the like. In the presentembodiment, the adhesive layer elements 45, 46, 47 are formed withrubber hot melt adhesive with high flexibility.

In the following description, the adhesive layer elements 45, 46, 47 arereferred to as “first adhesive layer elements 45”, “second adhesivelayer elements 46” and “third adhesive layer elements 47”, respectively,to distinguish one another. In the case where there is no need todistinguish the first adhesive layer elements 45, the second adhesivelayer elements 46 and the third adhesive layer elements 47, they arereferred to as the adhesive layer elements as a whole. In the apparatusfor manufacturing the absorbent product 1 in accordance with the presentembodiment, the plurality of adhesive layer elements are formed inalmost parallel, however the plurality of adhesive layer elements arenot necessarily formed in parallel. After one adhesive layer element outof the plurality of adhesive layer elements is formed, another adhesivelayer element may be formed.

The outer covering sheet 4 has two first adhesive layer elements 45located both end parts thereof in the vertical direction (i.e., thelongitudinal direction of the second covering sheet 42), and fifteenthird adhesive layer elements 47 arranged in the vertical direction andbeing adjacent to one another at the middle part of the second coveringsheet 42 (i.e., a midportion in the vertical direction). The outercovering sheet 4 further has three second adhesive layer elements 46arranged in the vertical direction and being adjacent to one another atan area between one first adhesive layer element 45 and the thirdadhesive layer element 47 nearest to the first adhesive layer element45, and three second adhesive layer elements 46 arranged in the verticaldirection and being adjacent to one another at an area between the otherfirst adhesive layer element 45 and the third adhesive layer element 47nearest to the first adhesive layer element 45. In other words, threesecond adhesive layer elements 46 are located at each of the front partand the back part in the second covering sheet 42.

Each first adhesive layer element 45 is formed by spiral sprayapplication and has wide width parts 451 each of which is formed byapplying string-like hot melt adhesive in a spiral form extending in theleft-right direction, and narrow width parts 452 each of which is formedby applying the string-like hot melt adhesive in a straight line formextending in the left-right direction. The narrow width parts 452 arenarrower than the wide width parts 451 with respect to the verticaldirection (i.e., a width of the narrow width parts 452 in the verticaldirection is smaller than that of the wide width parts 451). In thefirst adhesive layer element 45, the plurality of wide width parts 451and the plurality of narrow width parts 452 are arranged in theleft-right direction alternately and continuously, and a length of eachwide width part 451 in the left-right direction is almost equal to alength of each narrow width parts 452 in the left-right direction.

FIG. 6 is a flowchart showing a detailed operation flow of formation ofthe first adhesive layer elements 45, the second adhesive layer elements46 and the third adhesive layer elements 47 in Step S12. In theformation of each first adhesive layer element 45, while the string-likehot melt adhesive is discharged from a nozzle toward the second coveringsheet 42 moving from one side to the other side in the left-rightdirection, the hot melt adhesive is vibrated in the left-right directionand the vertical direction so as to draw approximate circles in a planarview by controlling a direction of gas ejected from gas outlets towardthe hot melt adhesive where the gas outlets are located around adischarging outlet of the nozzle, and therefore a wide width part 451 isformed (Step S121).

While the string-like hot melt adhesive is discharged from the nozzletoward the second covering sheet 42 moving as above, vibration of thehot melt adhesive in the left-right direction and the vertical directionis stopped by stopping ejection of the gas from the gas outlets (orejecting the gas in directions where discharging the hot melt adhesiveis unaffected), and therefore a narrow width part 452 is formed (StepS122).

The formation of wide width part 451 (Step S121) and the formation ofnarrow width part 452 (Step S122) in the first adhesive layer element 45are performed (repeated) alternately and continuously by a predeterminednumber of times (Step S123), and therefore the first adhesive layerelement 45 is completed. Here, if the left-right direction and thevertical direction of the absorbent product 1 are referred to as a“first direction” and a “second direction”, respectively, the wide widthparts 451 are formed by applying the string-like hot melt adhesive ontothe second covering sheet 42 along the first direction with vibration ofthe hot melt adhesive in the first direction and the second direction.The narrow width parts 452 are formed by applying the string-like hotmelt adhesive onto the second covering sheet 42 along the firstdirection without vibration of the hot melt adhesive in the seconddirection, and respective narrow width parts 452 are continuous with thewide width parts 451.

In the apparatus for manufacturing the absorbent product 1, anapplication quantity of the hot melt adhesive is controlled in Step S121and Step S122 and therefore, an application quantity of the hot meltadhesive per unit length in the left-right direction at the wide widthparts 451 is controlled so as to be more than that at the narrow widthparts 452 in the formation of the first adhesive layer element 45. Morespecifically, application control is performed so that a ratio of theapplication quantity per the unit length in the left-right direction atthe narrow width parts 452 to the application quantity per the unitlength at the wide width parts 451 becomes equal to a ratio of anapplication distance per the unit length in the left-right direction atthe narrow width parts 452 (the application distance is a length oftrajectory of the hot melt adhesive applied in a linear form and theapplication distance per the unit length is equal to the unit length) toan application distance (that is a length of trajectory of the hot meltadhesive applied in a spiral form) per the unit length in the left-rightdirection at the wide width parts 451. Therefore, a line width of theapplied hot melt adhesive is almost uniform at all portions of the widewidth parts 451 and the narrow width parts 452.

In the same way as the first adhesive layer elements 45, each secondadhesive layer element 46 is formed by spiral spray application and haswide width parts 461 each of which is formed by applying the string-likehot melt adhesive in a spiral form extending in the left-rightdirection, and narrow width parts 462 each of which is formed byapplying the string-like hot melt adhesive in a straight line formextending in the left-right direction. The narrow width parts 462 arenarrower than the wide width parts 461 with respect to the verticaldirection. Also in the second adhesive layer element 46, the pluralityof wide width parts 461 and the plurality of narrow width parts 462which are formed by processes shown in Steps S121 to S123 are arrangedin the left-right direction alternately and continuously, and formationof the wide width parts 461 and the narrow width parts 462 and controlof application quantity of the hot melt adhesive in the formation of thewide width parts 461 and the narrow width parts 462 are the same asthose in the above formation of the first adhesive layer elements 45.

In each second adhesive layer element 46, a length of each wide widthpart 461 is almost equal to a length of each narrow width part 462. Inthe three second adhesive layer elements 46 arranged in the verticaldirection, the plurality of wide width parts 461 in one second adhesivelayer element 46 are adjacent respectively, in the vertical direction,to the plurality of narrow width parts 462 in another second adhesivelayer element 46 which is adjacent to the one second adhesive layerelement 46. And the plurality of narrow width parts 462 in the onesecond adhesive layer element 46 are adjacent respectively, in thevertical direction, to the plurality of wide width parts 461 in theanother second adhesive layer element 46. In other words, the wide widthparts 461 and the narrow width parts 462 in the plurality of secondadhesive layer elements 46 are arranged staggeringly.

In the same way as the first adhesive layer elements 45 and the secondadhesive layer elements 46, each third adhesive layer element 47 isformed by spiral spray application and has wide width parts 471 each ofwhich is formed by applying the string-like hot melt adhesive in aspiral form extending in the left-right direction, and narrow widthparts 472 each of which is formed by applying the string-like hot meltadhesive in a straight line form extending in the left-right direction.The narrow width parts 472 are narrower than the wide width parts 471with respect to the vertical direction. Also in the third adhesive layerelement 47, wide width parts (or wide width part) 471 and narrow widthparts (or narrow width part) 472 which are formed by processes shown inSteps S121 to S123 are arranged in the left-right direction alternatelyand continuously, and formation of the wide width parts 471 and thenarrow width parts 472 and control of application quantity of the hotmelt adhesive in the formation of the wide width parts 471 and thenarrow width parts 472 are the same as those in the above formation ofthe first adhesive layer elements 45.

In each of the uppermost third adhesive layer element 47 and thelowermost third adhesive layer element 47 in FIG. 7, two wide widthparts 471 are provided at both ends in the left-right direction,respectively, and one relatively-long narrow width part 472 is providedbetween the two wide width parts 471. In each of the sixth and seventhelements 47 from the uppermost third adhesive layer element 47 in FIG.7, one relatively-long wide width part 471 is provided at almost middlein the left-right direction, and two narrow width parts 472 are providedon both left and right sides of the wide width part 471, respectively.In the other third adhesive layer elements 47, two wide width parts 471are provided in the vicinities of both ends in the left-right direction,respectively, one relatively-long narrow width part 472 is providedbetween the two wide width parts 471, and one narrow width parts 472 isprovided at the outside of each wide width part 471 in the left-rightdirection.

After the first adhesive layer elements 45, the second adhesive layerelements 46 and the third adhesive layer elements 47 are formed on thesecond covering sheet 42, as shown in FIG. 8, six leg elastic members 43and twenty-six waist elastic members 44 each of which is stretched arelocated on the second covering sheet 42 and they are bonded with thefirst adhesive layer elements 45, the second adhesive layer elements 46and the third adhesive layer elements 47 (Step S13). Three leg elasticmembers 43 are located along edges of the leg openings so as to beoverlapped (i.e., to contact) with the wide width parts 471 of each ofsix third adhesive layer elements 47 located at the upper side in FIG.8, and the three leg elastic members 43 are bonded on the secondcovering sheet 42 with the wide width parts 471 lying across them.

The other three leg elastic members 43 are located along edges of theleg openings so as to be overlapped (i.e., to contact) with the widewidth parts 471 of each of nine third adhesive layer elements 47 locatedat the lower side in FIG. 8, and the three leg elastic members 43 arebonded on the second covering sheet 42 with the wide width parts 471lying across them. In other words, the wide width parts 471 of the thirdadhesive layer elements 47 are located on areas where the leg elasticmembers 43 exist (in the present embodiment, they are located on onlythe areas) and the narrow width parts 472 are located on areas where theleg elastic members 43 do not exist (in the present embodiment, they arelocated on only the areas), in the absorbent product 1.

In the front part of the second covering sheet 42, four waist elasticmembers 44 are located along the upper edge of the second covering sheet42, and the four waist elastic members 44 are bonded on the secondcovering sheet 42 with the first adhesive layer element 45. Each of theplurality of wide width parts 451 in the first adhesive layer element 45lies across the four waist elastic members 44 in the vertical direction.Nine waist elastic members 44 are located almost parallel to theleft-right direction and bonded on the second covering sheet 42 with thethree second adhesive layer elements 46. Each of the plurality of widewidth parts 461 in the second adhesive layer elements 46 lies in thevertical direction across three waist elastic members 44 being adjacentto one another.

In the back part of the second covering sheet 42, four waist elasticmembers 44 are located along the lower edge of the second covering sheet42, and the four waist elastic members 44 are bonded on the secondcovering sheet 42 with the first adhesive layer element 45, in the sameway as the front part. Each of the plurality of wide width parts 451 inthe first adhesive layer element 45 lies across the four waist elasticmembers 44 in the vertical direction. Nine waist elastic members 44 arelocated almost parallel to the left-right direction and bonded on thesecond covering sheet 42 with the three second adhesive layer elements46. Each of the plurality of wide width parts 461 in the second adhesivelayer elements 46 lies in the vertical direction across three waistelastic members 44 being adjacent to one another.

After the leg elastic members 43 and the waist elastic members 44 arebonded on the second covering sheet 42, the first covering sheet 41shown in FIGS. 3 and 4 (practically, a continuous sheet body where aplurality of first covering sheets 41 are continuous in the left-rightdirection) are overlaid on the upper surface of the second coveringsheet 42 with the leg elastic members 43 and the waist elastic members44 lying between them, the first covering sheet 41 is bonded to thesecond covering sheet 42 with the first adhesive layer elements 45, thesecond adhesive layer elements 46 and the third adhesive layer elements47, and therefore the outer covering sheet 4 is formed (it is consideredthat these adhesive layer elements become one adhesive layer) (StepS14). It can be considered that Step S14 is a process where the legelastic members 43 and the waist elastic members 44 located between thefirst covering sheet 41 and the second covering sheet 42, are bonded tothe first covering sheet 41 and the second covering sheet 42 with thefirst adhesive layer elements 45, the second adhesive layer elements 46and the third adhesive layer elements 47.

In the apparatus for manufacturing the absorbent product 1 in accordancewith the present embodiment, although bonding of the first coveringsheet 41 to the second covering sheet 42 (Step S14) is performed afterbonding of the leg elastic members 43 and the waist elastic members 44to the second covering sheet 42 (Step S13), Step S13 and Step S14 may beperformed in parallel by locating the leg elastic members 43 and thewaist elastic members 44 on the upper surface of the second coveringsheet 42 in almost parallel with overlaying the first covering sheet 41on the upper surface of the second covering sheet 42.

As described above, in the outer covering sheet 4 of the absorbentproduct 1, since the first adhesive layer elements 45, the secondadhesive layer elements 46 and the third adhesive layer elements 47extending in the left-right direction on the second covering sheet 42comprise respectively the wide width parts 451, 461, 471 and the narrowwidth parts 452, 462, 472 which are continuous with the wide width parts451, 461, 471, the hot melt adhesive can be stably discharged across theentire length of each adhesive layer element, unlike in the case whereonly wide width parts are formed intermittently (i.e., the wide widthparts are isolated). Therefore, it is possible to obtain the outercovering sheet 4 which is a sheet member having the adhesive layerelements with desired shapes where unevenness is decreased (suppressed).And in the absorbent product 1 which is manufactured with use of thesheet member, comfort level of the wearer can be prevented fromdecreasing due to unevenness of thickness of the adhesive layer elementsand so on.

In the outer covering sheet 4, since the narrow width parts 452, 462,472 are provided to the first adhesive layer elements 45, the secondadhesive layer elements 46 and the third adhesive layer elements 47,breathability and softness of the outer covering sheet 4 can beincreased as compared with the case where whole the adhesive layerelements are made to be wide width parts. As the result, breathabilityand softness of the absorbent product 1 can be increased, and comfortlevel of the wearer to the absorbent product 1 can be increased. Inaddition, since the narrow width parts of each adhesive layer elementhas a linear shape extending in the left-right direction, a differencein width between the wide width parts and the narrow width parts can belarge. Therefore, breathability and softness of the outer covering sheet4 and the absorbent product 1 can be further increased. Furthermore, theplurality of wide width parts and the plurality of narrow width partswhich are arranged in the left-right direction alternately andcontinuously are provided in the adhesive layer element. Therefore,areas on which the adhesive layer elements are not formed are locatedalmost evenly on the second covering sheet 42. As the result,breathability and softness of the outer covering sheet 4 are increasedalmost uniformly.

As above, in the outer covering sheet 4, since the plurality of adhesivelayer elements are adjacent to one another in the vertical direction,the adhesive layer elements can be provided over a wide area on thesecond covering sheet 42. Therefore, the leg elastic members 43, thewaist elastic members 44 and the first covering sheet 41 are firmlybonded over the wide area on the second covering sheet 42. In twoadhesive layer elements adjacent to each other, the wide width parts inone adhesive layer element are adjacent to the narrow width parts in theother adhesive layer element in the vertical direction, respectively,and the narrow width parts in the one adhesive layer element areadjacent to the wide width parts in the other adhesive layer element inthe vertical direction, respectively. As the result, breathability andsoftness of the outer covering sheet 4 are increased more uniformly.

The outer covering sheet 4 comprises the first covering sheet 41 bondedon the second covering sheet 42. This increase tensile strength and thelike of the outer covering sheet 4, and breakage of the outer coveringsheet 4 by tension is suppressed when wearing the absorbent product 1 orthe like. Since the leg elastic members 43 and the waist elastic members44 are bonded between the first covering sheet 41 and the secondcovering sheet 42, stretchability can be given to the outer coveringsheet 4 easily. Furthermore, the wide width parts 471 of the thirdadhesive layer elements 47 are located on areas where the leg elasticmembers 43 exist, and the narrow width parts 472 are located on areaswhere the leg elastic members 43 do not exist (i.e., the areas arenonexistent areas). Therefore, the leg elastic members 43 can be firmlybonded to the first covering sheet 41 and the second covering sheet 42,and breathability and softness of areas on which the leg elastic members43 need not be bonded (i.e., each of the areas is located between a leftside portion and a right side portion of the almost U-shaped leg elasticmembers 43) can be increased. In the outer covering sheet 4, theplurality of leg elastic members 43 can be easily bonded to the firstcovering sheet 41 and the second covering sheet 42 by the wide widthparts 471 lying across the plurality of leg elastic members 43.

In the apparatus for manufacturing the absorbent product 1, since thestring-like hot melt adhesive is applied onto the second covering sheet42 along the left-right direction with vibration of the hot meltadhesive in the left-right direction and the vertical direction, thewide width parts can be formed easily. In addition, the adhesive layerelements are formed by spiral spray application, the wide width partsare formed as spiral curves of the hot melt adhesive, and thereforelines of the hot melt adhesive in each wide width part can bedensely-arranged. As the result, the leg elastic members 43 and thewaist elastic members 44 can be firmly bonded with them. Furthermore, adischarging quantity of the hot melt adhesive from the nozzle iscontrolled so that the application quantity of the hot melt adhesive perunit length in the left-right direction at the wide width parts is morethan that at the narrow width parts, and therefore variation of linewidths of the applied hot melt adhesive between the wide width parts andthe narrow width parts can be decreased.

FIG. 9 is a view showing another preferable example of adhesive layerelements. In FIG. 9, a portion in the vicinity of the upper end of asecond covering sheet 42 is drawn as an enlarged view, and a firstadhesive layer element 45 a which has a different shape from the firstadhesive layer elements 45 shown in FIGS. 7 and 8 is provided at theupper end of the second covering sheet 42. As shown in FIG. 9, a widthof the first adhesive layer element 45 a at each end portion of eachwide width part 451 gradually decreases toward an adjacent narrow widthpart 452, and the width at each end portion of each narrow width part452 gradually increases toward an adjacent wide width part 451. In thefirst adhesive layer element 45 a, when forming the portion where thewidth gradually decrease (or increase), a flow rate of gas ejectedtoward the hot melt adhesive discharged from the nozzle is made todecrease (or increase) gradually. As above, a border between the widewidth part 451 and the narrow width part 452 may be unclear, the portionwhose width is almost wide (relatively-wide) is the wide width part 451,and the portion whose width is almost narrow (relatively-narrow) is thenarrow width part 452.

In the absorbent product 1, a thickness of the outer covering sheet 4 ateach wide width part of the adhesive layer element is slightly largerthan that at each narrow width part. However, since the width of thefirst adhesive layer element 45 a gradually changes at boundary betweenthe wide width part 451 and the narrow width part 452 as describedabove, hardness variation of the outer covering sheet 4 caused by thefirst adhesive layer element 45 a can be smoothed. As the result, thefeel of the absorbent product 1 can be improved and the appearance ofthe absorbent product 1 can be also improved.

Next, discussion will be made on a sheet member in accordance with asecond preferred embodiment of the present invention. FIG. 10 is a planview showing a polymer sheet 4 a which is a sheet member in accordancewith the second preferred embodiment. For example, the polymer sheet 4 ais used as an absorbent core of the absorber 20 as a substitute for theabsorbent core 22 shown in FIG. 2 when manufacturing a pants-typedisposable diaper which is the absorbent product 1 in accordance withthe first preferred embodiment. Also the polymer sheet 4 a may be usedas an absorbent core of a absorbent product such as a tape-typedisposable diaper where a portion located on the front side of a wearerand a portion located on the back side are fastened around the waistlineof the wearer in wearing the disposal diaper or an auxiliary absorbentpad, or the polymer sheet 4 a may be used as a sheet main body ofnursing-care sheet which is a absorbent product to be put down under abody of a patient when changing the disposable diaper.

FIG. 11 is a cross-sectional view of the polymer sheet 4 a taken along aline XI-XI in FIG. 10. As shown in FIG. 11, the polymer sheet 4 a has afirst sheet 41 a and a second sheet 42 a each of which is formed of aliquid-pervious nonwoven fabric, plastic film or the like, a pluralityof adhesive layer elements 48 (in the present embodiment, four adhesivelayer elements 48) for bonding the first sheet 41 a to the second sheet42 a, and super absorbent materials 49 which lie between the first sheet41 a and the second sheet 42 a, and which are located at respectiveareas between the plurality of adhesive layer elements 48. Granulatedsuper absorbent polymers (SAP (Super Absorbent Polymer)), superabsorbent fibers or the like are used as the super absorbent materials49, and in the present embodiment, the granulated super absorbentpolymers are used. In FIG. 11, the super absorbent materials 49 areenlarged for easy understanding of the drawing. In FIG. 10, the adhesivelayer elements 48 are drawn with thin solid lines (the same applies toFIGS. 13 to 17).

The plurality of adhesive layer elements 48 each extending in theleft-right direction of FIG. 10 are adjacent to one another in thevertical direction of FIG. 10. Each of the plurality of adhesive layerelements 48 has a plurality of wide width parts 481 and a plurality ofnarrow width parts 482 each of which are formed by applying thestring-like hot melt adhesive in a spiral form extending in theleft-right direction. The plurality of wide width parts 481 and theplurality of narrow width parts 482 are arranged in the left-rightdirection of FIG. 10 alternately and continuously in each adhesive layerelement 48.

A width of the adhesive layer element 48 (i.e., the width in thevertical direction of FIG. 10) gradually decreases from the middle ofeach wide width part 481 in the left-right direction toward the narrowwidth parts 482 adjacent to the wide width part 481, and the widthgradually increases from the middle of each narrow width part 482 in theleft-right direction toward the wide width parts 481 adjacent to thenarrow width part 482. As above, in each adhesive layer element 48, thewidth of each wide width part 481 and each narrow width part 482gradually changes along the left-right direction, and therefore aplurality of approximate rhombus patterns are arranged along theleft-right direction.

In the four adhesive layer elements 48 arranged in the verticaldirection of FIG. 10, the plurality of wide width parts 481 in oneadhesive layer element 48 are adjacent respectively, in the verticaldirection, to the plurality of wide width parts 481 in another adhesivelayer element 48 which is adjacent to the one adhesive layer element 48.And the plurality of narrow width parts 482 in the one adhesive layerelement 48 are adjacent respectively, in the vertical direction, to theplurality of narrow width parts 482 in the another adhesive layerelement 48.

FIG. 12 is a flowchart showing an operation flow for manufacturing thepolymer sheet 4 a. In the manufacture of the polymer sheet 4 a, first,the second sheet 42 a shown in FIG. 11 is prepared (Step S21), and theplurality of adhesive layer elements 48 are formed on the second sheet42 a (Step S22). In formation of the wide width parts 481 and the narrowwidth parts 482 of each adhesive layer element 48, gradually increasinga flow rate of gas ejected toward the hot melt adhesive discharged fromthe nozzle and gradually decreasing the flow rate are repeatedcontinuously.

Therefore, the string-like hot melt adhesive is applied onto the secondsheet 42 a along the left-right direction of FIG. 10 while the hot meltadhesive is vibrated in the left-right direction and the verticaldirection with change in the amplitude of the vertical direction (theamplitude in the left-right direction may be also changed), so that theplurality of wide width parts 481 and the plurality of narrow widthparts 482 which are continuous in the left-right direction are formed onthe second sheet 42 a. Although the plurality of adhesive layer elements48 are formed in almost parallel with one another in the presentembodiment, formation of the plurality of adhesive layer elements 48 isnot necessarily performed in parallel manner. After one adhesive layerelement 48 of the plurality of adhesive layer elements 48 is formed,another adhesive layer element 48 may be formed.

In the formation of the adhesive layer elements 48, an applicationquantity of the hot melt adhesive per unit length in the left-rightdirection at the wide width parts 481 is controlled so as to be morethan that at the narrow width parts 482 in similar way to the firstpreferred embodiment. Therefore, a line width of the applied hot meltadhesive is almost uniform at all portions of the wide width parts 481and the narrow width parts 482.

After the formation of the adhesive layer elements 48 is finished, thesuper absorbent materials 49 are located at an area between each twoadhesive layer elements 48 adjacent to each other as shown in FIG. 11(Step S23). After that, the first sheet 41 a is bonded to the secondsheet 42 a with the four adhesive layer elements 48 (Step S24).

As described above, in the polymer sheet 4 a, each adhesive layerelement 48 comprises the wide width parts 481 and the narrow width parts482 which are continuous with the wide width parts 481, respectively,and therefore the hot melt adhesive can be stably discharged across theentire length of the adhesive layer element 48 in similar fashion to thefirst preferred embodiment. As the result, it is possible to obtain thepolymer sheet 4 a which is a sheet member having the adhesive layerelements 48 with desired shapes where unevenness is decreased.

In the adhesive layer element 48, since the plurality of wide widthparts 481 and the plurality of narrow width parts 482 are arranged inthe left-right direction of FIG. 10 alternately and continuously,hardness variation of the polymer sheet 4 a caused by the adhesive layerelements 48 can be smoothed in similar fashion to the first preferredembodiment. In addition, since the width of each wide width part 481 andeach narrow width part 482 gradually changes along the left-rightdirection of FIG. 10 and the plurality of approximate rhombus patternsare arranged along the left-right direction, thickness variation (orthickness difference) of the polymer sheet 4 a caused by the adhesivelayer elements 48 can be further reduced. As the result, the feel andthe appearance of the absorbent product 1 can be improved.

The plurality of adhesive layer elements 48 which are adjacent to oneanother in the vertical direction of FIG. 10 are provided in the polymersheet 4 a, the wide width parts 481 in one adhesive layer element 48 oftwo adhesive layer elements 48 adjacent each other are adjacentrespectively, in the vertical direction, to the wide width parts 481 inthe other adhesive layer element 48, and the narrow width parts 482 inthe one adhesive layer element 48 are adjacent respectively, in thevertical direction, to the narrow width parts 482 in the other adhesivelayer element 48. Therefore, in the polymer sheet 4 a, approximaterhombus patterns of the applied hot melt adhesive and approximaterhombus areas where the hot melt adhesive is not applied (the areas arenonexistent areas of adhesive) are located almost evenly. As the result,breathability and softness of the polymer sheet 4 a are increased almostuniformly.

In the polymer sheet 4 a, the super absorbent materials 49 are locatedat an area between each two adhesive layer elements 48 adjacent to eachother (i.e., the area is parts of the above nonexistent areas ofadhesive) with the materials lying between the first sheet 41 a and thesecond sheet 42 a, and therefore the super absorbent materials 49 canmove within the nonexistent areas of adhesive. Thus, when a wearer putson the absorbent product where the polymer sheet 4 a is used, the superabsorbent materials 49 move within the nonexistent areas of adhesive soas to make the polymer sheet 4 a along the body of the wearer. As theresult, it is possible to easily deform the absorbent product where thepolymer sheet 4 a is used, so as to fit the body of the wearer.

FIG. 13 is a plan view showing another example of polymer sheet. Thepolymer sheet 4 b shown in FIG. 13 comprises four adhesive layerelements 48 each having the same structure as the adhesive layerelements 48 of the polymer sheet 4 a shown in FIG. 10, and theseadhesive layer elements 48 are arranged in the vertical direction ofFIG. 13. In the polymer sheet 4 b, the plurality of wide width parts 481in one adhesive layer element 48 are adjacent respectively, in thevertical direction, to the plurality of narrow width parts 482 inanother adhesive layer element 48 which is adjacent to the one adhesivelayer element 48. And the plurality of narrow width parts 482 in the oneadhesive layer element 48 are adjacent respectively, in the verticaldirection, to the plurality of wide width parts 481 in the anotheradhesive layer element 48.

In the polymer sheet 4 b, since super absorbent materials such as superabsorbent polymers or super absorbent fibers are located at respectiveareas between the plurality of adhesive layer elements 48, it ispossible to easily deform the absorbent product where the polymer sheet4 b is used, so as to fit the body of the wearer in similar fashion tothe polymer sheet 4 a. Also breathability and softness of the polymersheet 4 b are increased almost uniformly.

Though the preferred embodiments of the present invention have beendiscussed above, the present invention is not limited to theabove-discussed preferred embodiments, but allows various variations.

For example, in the manufacture of the absorbent product 1 in accordancewith the first preferred embodiment, three leg elastic members 43 arebonded at each of an upper half and a lower half of the middle part ofthe second covering sheet 42 shown in FIG. 8, however, one or two legelastic members 43, or leg elastic members 43 more than three may bebonded at each of the upper half and the lower half of the middle part.

In the manufacture of absorbent product 1, there may be the case whereduring formation of the long narrow width part 472 between two widewidth parts 471 of the third adhesive layer element 47 shown in FIG. 7,discharging the hot melt adhesive is temporarily stopped and an areawhere the hot melt adhesive is not applied is provided at a middle ofthe narrow width part 472. In this case, each of portions on both sides(left side and right side) of the area is one adhesive layer elementcomprising two narrow width parts 472 and one wide width part 471located between them.

In the absorbent product 1, the hot melt adhesive may be applied ontothe first covering sheet 41 also. For example, bonding between the firstcovering sheet 41 and the second covering sheet 42 may be performed withhot melt adhesive applied all over the lower surface of the firstcovering sheet 41 (i.e., the surface faces the second covering sheet 42)by slit coating or the like, and the first adhesive layer elements 45,the second adhesive layer elements 46 and the third adhesive layerelements 47 on the second covering sheet 42. Applied adhesive other thanthe first adhesive layer elements 45, the second adhesive layer elements46 and the third adhesive layer elements 47 may be provided on thesecond covering sheet 42. For example, the adhesive is applied uniformlyon non-application areas between the first adhesive layer elements 45,the second adhesive layer elements 46 and the third adhesive layerelements 47 or on positions overlapping with these adhesive layerelements.

Also in the polymer sheet 4 a in accordance with the second preferredembodiment, the hot melt adhesive is applied onto the lower surface ofthe first sheet 41 a (i.e., the surface faces the second sheet 42 a) andbonding between the first sheet 41 a and the second sheet 42 a may beperformed with the applied hot melt adhesive and the adhesive layerelements 48 on the second sheet 42 a. Applied adhesive other than theadhesive layer elements 48 may be provided on the second sheet 42 a. Forexample, the adhesive is applied uniformly on non-application areaswhere the adhesive layer elements 48 are not formed or on positionsoverlapping with the adhesive layer elements 48.

In the polymer sheet 4 a, the super absorbent materials 49 are notnecessarily located at all the nonexistent areas of adhesive as long asthey are located at least at an area between any two adhesive layerelements 48. Also the super absorbent materials 49 may be located on theadhesive layer elements 48. For example, the super absorbent materials49 are evenly located almost all over the surface of the second sheet 42a.

Each adhesive layer element of the absorbent product 1 and the polymersheet 4 a is not necessarily formed by spiral spray application, and itmay be formed by another application. For example, in the case where adirection in which each adhesive layer element 48 a extends is a firstdirection and a direction orthogonal to the first direction is a seconddirection, the string-like hot melt adhesive is discharged along thefirst direction (i.e., with relative movement in the first direction)with vibration of the hot melt adhesive in the first direction and thesecond direction, and therefore as shown in FIG. 14, the hot meltadhesive is applied in Ω (omega) forms to form a wide width part 481 a.

In each of adhesive layer elements 48 b, 48 c shown respectively inFIGS. 15 and 16, the string-like hot melt adhesive is discharged alongthe first direction with vibration of the hot melt adhesive in thesecond direction, and therefore the hot melt adhesive is applied in asinusoidal form or zigzag form to form a wide width part 481 b, 481 c.As above, in the formation of adhesive layer element, the wide widthpart is formed by applying the string-like hot melt adhesive along thefirst direction with vibration of the hot melt adhesive at least in thesecond direction. In adhesive layer elements 48 d shown in FIG. 17,narrow width parts 482 d which are narrower in the second direction thanwide width parts 481 d are formed by applying the string-like hot meltadhesive along the first direction with vibration of the hot meltadhesive in the first direction and the second direction in similarfashion to the wide width parts 481 d.

In formation of each adhesive layer element of the absorbent product 1and the polymer sheet 4 a, an application quantity of the hot meltadhesive per unit length at the wide width parts is not necessarilycontrolled so as to be more than that at the narrow width parts (i.e.,the application quantity of the hot melt adhesive per the unit length atthe narrow width parts). For example, the application quantity of thehot melt adhesive per the unit length may be uniform across the entirelength of the adhesive layer element. In addition, adhesive to form eachadhesive layer element is not limited to the hot melt adhesive, and theabove adhesive layer elements may be formed with another type ofadhesive.

In the above preferred embodiments, the outer covering sheet 4 ofdouble-layered structure comprising the first covering sheet 41 and thesecond covering sheet 42, and the polymer sheet 4 a of double-layeredstructure comprising the first sheet 41 a and the second sheet 42 a areexemplified as a sheet member in accordance with the present invention,however the sheet member need not have the double-layered structure, andthe sheet member may be used as various members other than the outercovering sheet 4 and the polymer sheet 4 a for manufacturing variousabsorbent products.

For example, as shown in FIG. 18, the sheet member is bonded on eachside portion of the main body part 2 to become the side sheet 3 in themanufacture of the absorbent product 1 in accordance with the firstpreferred embodiment. As shown in FIG. 18, an adhesive layer element 48e extending in the longitudinal direction of the main body part 2 isformed with the hot melt adhesive at the side wall end part 341 of theside sheet 3, and the adhesive layer element 48 e has a wide width part481 and a narrow width part 482 which is continuous with the wide widthpart 481 in the longitudinal direction. The side wall end part 341 ofthe side sheet 3 is bonded on the main body part 2 with the adhesivelayer element 48 e. Therefore, it is possible to make a portion of theside sheet 3 be standing toward the wearer's side at the side wall endpart 341 and to gradually lower the height of the standing portiontoward the end of the main body part 2 in the longitudinal direction.

In the apparatus for manufacturing the absorbent product 1 in accordancewith the first preferred embodiment, an adhesive layer element having awide width part and a narrow width part may be utilized for bondingbetween the absorber 20 and the outer covering sheet 4. In the casewhere the adhesive layer element is formed on the outer covering sheet4, the outer covering sheet 4 or the first covering sheet 41 is treatedas a sheet of a sheet member in accordance with the present invention.On the other hand, in the case where the adhesive layer element isformed on the lower surface of the absorber 20, the absorber 20 or theback sheet 23 of the main body part 2 is treated as the sheet of thesheet member. Also the above adhesive layer element may be used forbonding between the end holding sheet 5 and the outer covering sheet 4.In this case, the outer covering sheet 4 or the first covering sheet 41,or the end holding sheet 5 is treated as the sheet of the sheet member.

While the invention has been shown and described in detail, theforegoing description is in all aspects illustrative and notrestrictive. It is therefore understood that numerous modifications andvariations can be devised without departing from the scope of theinvention. This application claims priority benefit under 35 U.S.C.Section 119 of Japanese Patent Application No. 2009-220728 filed in theJapan Patent Office on Sep. 25, 2009, the entire disclosure of which isincorporated herein by reference.

REFERENCE SIGNS LIST

-   -   1 absorbent product    -   3 side sheet    -   4 outer covering sheet    -   4 a, 4 b polymer sheet    -   5 end holding sheet    -   22 absorbent core    -   23 back sheet    -   41 first covering sheet    -   41 a first sheet    -   42 second covering sheet    -   42 a second sheet    -   43 leg elastic member    -   44 waist elastic member    -   45, 45 a first adhesive layer element    -   46 second adhesive layer element    -   47 third adhesive layer element    -   48, 48 a to 48 e adhesive layer element    -   49 super absorbent materials    -   451, 461, 471, 481, 481 a to 481 d wide width part    -   452, 462, 472, 482, 482 d narrow width part    -   S11 to S14, S21 to S24, S121 to S123 step

The invention claimed is:
 1. A sheet member to be used for manufacturingan absorbent product, the sheet member comprising: a sheet; and anadhesive layer element lying on said sheet and extending in a firstdirection; wherein said adhesive layer element comprises: a wide widthpart which is formed by applying string-like adhesive onto said sheetalong said first direction with vibration of said adhesive in a seconddirection orthogonal to said first direction to form a pattern of thestring-like adhesive which has an amplitude in the second direction; anda narrow width part which is narrower than said wide width part andwhich is formed by applying said string-like adhesive onto said sheetalong said first direction with or without vibration of said adhesive insaid second direction, said narrow width part being continuous with saidwide width part, wherein a width of said adhesive layer element, whichis the amplitude in said second direction, has a gradual change at aboundary between said wide width part and said narrow width part, thegradual change including multiple oscillating, forms of incrementallysmaller amplitudes; wherein the adhesive layer element includes aplurality of rhombus patterns, each rhombus pattern including multipleoscillating forms of incrementally smaller amplitudes.
 2. The sheetmember according to claim 1, wherein said narrow width part has a linearshape extending in said first direction.
 3. The sheet member accordingto claim 1, wherein said adhesive layer element comprises a plurality ofwide width parts and a plurality of narrow width parts which arearranged in said first direction alternately and continuously.
 4. Thesheet member according to claim 3, wherein a width of each wide widthpart and each narrow width part gradually changes along said firstdirection, and a plurality of rhombus patterns are arranged along saidfirst direction in said adhesive layer element.
 5. The sheet memberaccording to claim 3, further comprising another adhesive layer elementwhich has the same structure as said adhesive layer element, extendingin said first direction and being adjacent to said adhesive layerelement in said second direction.
 6. The sheet member according to claim5, wherein said plurality of wide width parts in said adhesive layerelement are adjacent to a plurality of narrow width parts in saidanother adhesive layer element in said second direction, respectively,and said plurality of narrow width parts in said adhesive layer elementare adjacent to a plurality of wide width parts in said another adhesivelayer element in said second direction, respectively.
 7. The sheetmember according to claim 4, further comprising another adhesive layerelement which has the same structure as said adhesive layer element,extending in said first direction and being adjacent to said adhesivelayer element in said second direction, wherein said plurality of widewidth parts in said adhesive layer element are adjacent to a pluralityof wide width parts in said another adhesive layer element in saidsecond direction, respectively, and said plurality of narrow width partsin said adhesive layer element are adjacent to a plurality of narrowwidth parts in said another adhesive layer element in said seconddirection, respectively.
 8. The sheet member according to claim 1,further comprising another sheet which is bonded to said sheet with saidadhesive layer element.
 9. The sheet member according to claim 8,further comprising an elastic member which is located between said sheetand said another sheet and which is bonded to said sheet and saidanother sheet with said adhesive layer element.
 10. The sheet memberaccording to claim 9, wherein said wide width part of said adhesivelayer element is located on an area where said elastic member exists andsaid narrow width part is located on an area where said elastic memberdoes not exist.
 11. The sheet member according to claim 9, furthercomprising another elastic member which is located between said sheetand said another sheet and which is bonded to said sheet with saidadhesive layer element together with said elastic member.
 12. The sheetmember according to claim 5, further comprising: another sheet which isbonded to said sheet with said adhesive layer element and said anotheradhesive layer element; and super absorbent polymers or super absorbentfibers which lie between said sheet and said another sheet, and whichare located at least at an area between said adhesive layer element andsaid another adhesive layer element.
 13. The sheet member according toclaim 1, wherein said adhesive layer element is formed by spiral sprayapplication.
 14. The sheet member according to claim 1, wherein anapplication quantity of said adhesive per unit length in said firstdirection at said wide width part is more than that at said narrow widthpart.
 15. The sheet member according to claim 1, wherein the wide widthpart is a string-like adhesive applied to said sheet in a sinusoidalform or a zigzag form, and the width of the wide width part is formed bythe amplitude of the sinusoidal form or the zigzag form.
 16. Anabsorbent product comprising: the sheet member of claim 15, wherein thesheet is a first covering sheet; a second covering sheet; an elasticmember disposed between said first covering sheet and said secondcovering sheet; a top sheet; and an absorbent core disposed between saidfirst covering sheet and said top sheet.
 17. The absorbent product ofclaim 16, wherein the absorbent product has a waist opening and two legopenings.
 18. An absorbent product comprising: the sheet member of claim1, wherein the sheet is a first covering sheet; a second covering sheet;an elastic member disposed between said first covering sheet and saidsecond covering sheet; a top sheet; and an absorbent core disposedbetween said first covering sheet and said top sheet.
 19. The absorbentproduct of claim 18, wherein the absorbent product has a waist openingand two leg openings.